Fix data alignment on the backend

pkg/timeseries/align.go

@@ -35,6 +35,36 @@ func (ts TimeSeries) Align(interval time.Duration) TimeSeries {
 	return alignedTs
 }
 
+// Fill missing points in trend by null values
+func (ts TimeSeries) FillTrendWithNulls() TimeSeries {
+	if ts.Len() < 2 {
+		return ts
+	}
+
+	interval := time.Hour
+	alignedTs := NewTimeSeries()
+	var frameTs = ts[0].GetTimeFrame(interval)
+	var pointFrameTs time.Time
+	var point TimePoint
+
+	for i := 0; i < ts.Len(); i++ {
+		point = ts[i]
+		pointFrameTs = point.GetTimeFrame(interval)
+
+		if pointFrameTs.After(frameTs) {
+			for frameTs.Before(pointFrameTs) {
+				alignedTs = append(alignedTs, TimePoint{Time: frameTs, Value: nil})
+				frameTs = frameTs.Add(interval)
+			}
+		}
+
+		alignedTs = append(alignedTs, point)
+		frameTs = frameTs.Add(interval)
+	}
+
+	return alignedTs
+}
+
 // Detects interval between data points in milliseconds based on median delta between points.
 func (ts TimeSeries) DetectInterval() time.Duration {
 	if ts.Len() < 2 {